Follow these simple steps:
1. Go to
youtube-grab.com
2. Go to the YouTube video you want to download and copy the video URL (found at the top of your browser)
3. Go back to youtube-grab and paste the URL in the text box
4. Choose a conversion type (mp3 or mp4)
5. Click "Convert"
6. Wait for few seconds to complete the conversion and the file will be available for download